1. Technical Field
Methods and apparatuses consistent with the present invention generally relate to the testing of a sleep support member. More particularly, methods and apparatuses consistent with this invention relate to the testing of a mattress by simulating heat and/or moisture released by a person sleeping on the mattress and/or by simulating movement of the person sleeping on the mattress.
2. Description of the Related Art
There are several conventional tests for simulating the weight of a user sleeping on a mattress in order to determine the durability of the mattress. For example, the Cornell Testing Machine tests the durability of a mattress by repeatedly subjecting the mattress to a large force. Another example, the Mattress Rollator Machine, includes a weighted roller that simulates the weight and movement of a user by moving widthwise across the mattress. A mattress that has been subjected to these tests is evaluated based on how well it maintains its shape and support firmness.
In addition, U.S. Pat. No. 6,585,328 (the '328 patent), which is incorporated herein by reference in its entirety, and was invented by the same inventors as the present application, discloses a mattress evaluation system in which the deflection characteristics of the mattress are determined by simulating the weight of a sleeping person. That is, multiple pressure plates or platens are depressed downwardly into the mattress. The plates or platens are arranged so that the location of each plate or platen replicates a part of the person. Each platen is depressed by a pressure piston to simulate the weight of the person on the mattress. The suitability of the mattress for a person of a particular size is determined based on the sensed pressures.
However, each of these conventional systems has disadvantages because, although they simulate weight and movement on a mattress, they do not accurately simulate the movement of a human body on the mattress, the heat and/or moisture released from the human body, or the environmental conditions in which the mattress is used. For example, when the user of a mattress releases heat and perspires, the heat and perspiration can break down the fibers, foams and other soft materials on the top of the mattress. This can leave a permanent body impression or indentation in the mattress, which is a major problem especially with the plush materials employed in conventional mattresses.
Moreover, the mattress user typically changes his/her body position several times during the night, thus applying different pressures to different parts of the mattress. Conventional testing systems are not able to simulate this kind of motion and the resulting fatigue stress on the mattress.
Finally, the durability of a mattress changes based on the environmental conditions to which the mattress is exposed. Conventional testing systems are not able to simulate the environmental conditions in which the mattress is used.